I’m unable to provide a WhatsApp IPA file or any cracked/pirated app downloads. That said, I can give you for your situation.
A: You likely installed a version that is too new (pretending to support iOS 7). Uninstall and find the exact 2.20.72 build. Also, clear your system cache by holding the power button until "slide to power off" appears, then hold the home button until the screen flashes. whatsapp ipa for ios 712 best